Enlightenment, Hampstead Theatre, London

In one way it's business as usual at the Hampstead Theatre, a venue that draws its local audience from an area whose population is the densest in Europe – wait, the sentence isn't finished – with artists and writers. As before, the play takes on serious ideas and emotions but merely dabbles in them. But this first offering from Edward Hall, the new artistic director (who also directs the play) is a great step forward. While Hampstead plays, for the past several years, have delivered only irritation, dyspepsia and disbelief, Enlightenment is generous with entertainment – clever comedy, attractive and accomplished actors, a sparkling production. Rome wasn't built in a day.

That last observation is not much less a cliché than many spoken by Shelagh Stephenson's characters, or embodied by the play. Adam, the 20-year-old son of Lia and stepson of Nick, has not been heard from since a terrorist attack in the Far East, where he has been travelling. Desperate to believe he is alive, Lia calls in a particularly unconvincing psychic and agrees to take part in a TV programme. Suddenly she hears that Adam has been found, but the young man who walks in is a stranger who, having woken up next to a bag filled with Adam's possessions, assumed his identity.

Francis O'Connor's set – a cartoon-like drawing room of clear plastic chairs and books bound in primary colours – smartly evokes its characters' world: Nick is a professor, Lia the art-loving daughter of a former Labour minister. But it also reflects their stylish superficiality. Though the characters talk of chaos theory and the disproportionate use by the West of the world's resources, these subjects are dealt with briefly and in isolation from the plot, one familiar from Six Degrees of Separation and Entertaining Mr Sloane. The play only skirts a topic closer to home – the prosperity and materialism that have kept adults in the infantile state of believing that they can have anything and that they deserve it. Stephenson also makes her characters real or ridiculous, thoughtful or thin as it suits her.

One does believe, however, in Julie Graham's Lia as a woman both intelligent and sensual. Enlightenment may not be illuminating, but while this actress, who suggests a softer but equally forceful Clare Higgins, is on stage, it glows.

To 30 October (0207 722 9301)